1. Field of the Invention
This present invention relates to cutting blades, particularly to cutting blades having repeating patterns of teeth formed in sequence throughout the cutting blade and, more particularly, to cutting blades for use with power driven, wood cutting saws, wherein the blades have patterns of set teeth that include one or more surface features in order to promote the flow of swarf into the gullets of the blade rather than onto the surface of objects cut by the blade.
2. Description of Related Art
Cutting tools, such as power saws, have existed for many years, during which it has remained a goal for the saws to be able to cut objects (e.g., wood) quickly and uniformly, while allowing the saws to be safe and energy efficient.
Among the steps taken to reach this goal was to set some of the teeth of the cutting blades of such saws at an angle with respect to the jaw line and/or longitudinal axis of the blade. This causes the sharp tips of the set teeth to be exposed to the surface of the object(s) to be cut, and enables the blade to cut a width (i.e., xe2x80x9ckerfxe2x80x9d) of the object(s) greater than the thickness of the blade, thus allowing for quicker, more efficient passage of the blade through the object(s).
FIG. 1 depicts an exemplary blade 10 for a power saw that includes a plurality of non-set teeth 12a, 12b and set teeth 14a, 14b. In this instance, the proximal set tooth 14a is set to the left with respect to a longitudinal axis 16 of the blade, while the distal set tooth 14b is set to the right with respect to the axis such that the set teeth 14a, 14b form a face angle, xcex4, of about xe2x88x9212xc2x0.
During cutting of a wood-based object with this cutting blade 10, swarf (e.g., sawdust or other cutting residue) is necessarily produced by the cutting action of the blade. As the cutting blade 10 continues to move in a proximal-to-distal direction while cutting the object, the swarf follows a path as shown by the small arrows depicted in FIG. 1.
Ideally, as much swarf as possible is kept away from the surface of the object that is being cut by the blade. This is because any swarf that contacts and adheres to the cutting surface of the object will interfere with the cutting action of the blade and, in turn, will necessarily impede the blade""s ability to cut an object with maximum efficiency and/or uniformity.
The lack of uniformity of cuts produced by a blade is a significant problem in any usage environment because it results in finished products that possess unintended dimensions and/or unattractive appearances or surface finishes. And while the lack of efficiency of a cutting blade is disadvantageous in any usage environment, it is particularly problematic in high output environments (e.g., saw mills), where it results in marked increases in the amount of time needed to cut large quantities of objects, the amount of energy/power required to cut the objects and, in turn, in the service life of the blade itself.
Unfortunately, this blade 10 (and other blades like it), despite having a teeth arrangement as shown in FIGS. 1, 1A and 1B, have not proven effective in curbing the flow of swarf onto the cutting surface of the object(s) being cut.
Therefore, a need exists for a cutting blade, and a method of making such a blade, wherein the combination of the geometry and the surface features of the blade promotes a reduction in the incidence of swarf contacting and adhering to the surface of the object(s) being cut, so as to enable the cutting blade to provide for more quick, reliable and energy efficient cutting of such object(s), and for such object(s) to have a more attractive surface finish.
The following patents are related to the present invention as background information. The disclosures of each patent are hereby incorporated herein by reference in their entirety:
The present invention provides cutting blades for cutting tools and methods of making such blades. While the invention is primarily described with regard to wood cutting power driven saws, it is applicable to a variety of power driven cutting tools for cutting a variety of materials, such tools including, but not limited to, band saws, circular saws and portable saw mills, and such materials including, but not limited to, metals or alloys (e.g., steel).
In an exemplary aspect of the present invention, a cutting blade includes a repeating tooth pattern that is comprised of both set and non-set teeth. Preferably, this is a three-tooth pattern that comprises one non-set tooth, one tooth set to the left of the longitudinal axis of the blade and one tooth set to the right side of the longitudinal axis.
The set teeth form a positive face angle and a Y-shape about the longitudinal axis of the blade. This particular arrangement of set teeth is advantageous because it is less prone to cutting xe2x80x9coff-squarexe2x80x9d as the teeth become dull.
Each of the set teeth of a blade in accordance with the present invention includes one or more surface features in order to reduce the disadvantageous incidence of swarf contacting and adhering to the surface of the object being cut by the blade. Each surface feature is located between the tip of a set tooth and the jaw line of the blade, preferably very close to the jaw line. The term xe2x80x9cjaw line,xe2x80x9d as used herein, represents the physical center line/position of the blade.
Preferably, each of these surface features is, or has the appearance of, a positive surface feature, such as a notch, a step, a peak, a bump, a point, or a discontinuity. One, some or all of these surface features, however, may be, or may have the appearance of, a negative surface feature (e.g., a valley).
The presence of the surface feature(s) increases the likelihood that at least some of the swarf produced during the cutting process will be beneficially directed into one or more of the gullets present in the cutting blade in lieu of disadvantageously being directed into/onto the surface of the object being cut by the blade.
In an exemplary aspect of the present invention, at least some swarf travels down a tooth and impacts one or more surface features present on the tooth, thus slowing the downward descent of the swarf enough to allow the swarf to be caught in the gullet immediately proximal that particular tooth.
Once trapped within the gullet, the swarf will remain there until the blade goes around a wheel (thus causing the swarf to fall out of the gullets) and/or until air or brushes (or both) forcibly remove the collected swarf from the gullets and into/onto a collection area (e.g., the floor).
The present invention also provides methods of making cutting blades that include set teeth with one or more of such surface features.
In an exemplary aspect of a method of the present invention, some of the teeth of a preformed saw blade for a power driven cutting tool are caused to be xe2x80x9csetxe2x80x9d (i.e., bent and/or twisted at an angle) with respect to the longitudinal axis of the blade. A portion between the jaw line of the blade and the tip of each tooth is then ground using one or more grinding tools.
This grinding defines a surface remnant having the appearance of either a positive or negative surface feature and, preferably, also creates a grinding pattern (e.g., striations). These striations assist in causing swarf to be directed into gullets of the blade in accordance with the invention.
The methods according to the present invention are simple and inexpensive to implement, and result in cutting blades that are believed to be superior to comparable blades that are currently available.
In particular, the blades of the present invention reduce the problem of swarf accumulation on the surface of an object while that object is being cut by the blade.
Such accumulated swarf necessarily inhibits the blade""s ability to cut objects with maximum efficiency such that comparatively more time, effort and (perhaps most importantly) more electrical power are required to cut the object as would be needed if the amount of swarf accumulation at the surface of the object being cut was reduced. The presence of swarf on the object being cut also tends to cause the blade to impart less uniform cuts to the object, which, in turn, results in the cut object having unintended dimensions and/or an unattractive appearance or surface finish.
By reducing the accumulation of swarf on the surface of the object being cut by a cutting blade, the present invention is effective in reducing the incidence of these, and other problems caused by such swarf accumulation.